Not that I want these things to get any more popular than they already are, but...
I've become a big fan of old brass LF lenses lately. In addition to the big names - Dagor, Protar, T-R Triple - I've picked up quite a few no-name or somewhat obscure examples. On a LF excursion to Governors Island National Monument a few weeks ago, I packed my 4x5 Speed and four lenses - a 4x5 Gundlach doublet, Gundlach 5x7 Rectigraphic Triple, 125mm Dagor, and 210mm brass barrel Dagor.
Here's a photo of the Gundlach and one of Fort Jay, courtesy of that lens and a sheet of Delta 100. The lens came my way on the bay as part of a lot of 6 - an Ektar 127, 5x7 B&L RR, and three Seneca 4x5 Anastigmats. Turned out to be the gem of the bunch.
I always like to see what other are doing with their antiques so I'm hoping y'all follow my lead and share some favorite sleepers (so I can hunt them down and snap them up for myself)